1. Field of the Invention
This invention relates to a serial-type recording apparatus which performs recording by reciprocating recording means along a recording medium and more particularly to a recording apparatus which performs the reciprocating operation of the recording means and the conveyance operation of the recording medium by means of a common motor.
2. Related Background Art
In years past, there has been known a serialtype small recording apparatus which performs recording by reciprocating a recording head along a recording sheet. A typical recording apparatus in which the reciprocating operation of the recording head and the conveyance operation of the recording sheet are carried out by use of a common motor has been constructed by independently disposing an advance groove and a return groove on a rod-like member so as to form a spiral groove thereon and coupling both ends of the spiral groove. The recording operation of such a recording apparatus has generally been made by inserting into the above-mentioned spiral groove a member projecting from a carriage on which the recording head is mounted and by causing the rod-like member to rotate in one direction so as to reciprocate the carriage.
In such a recording apparatus as specified above, it has been customarily practiced that the recording operation is limited to the advance and return operation and the operation process when the carriage returns is assigned to the conveyance operation of the recording sheet.
However, the conventional apparatus having such arrangements stated above includes the following problems to be solved.
(i) Since the advance and return grooves are provided on the same shaft by cutting a metallic shaft, the production costs increase.
(ii) Instead, it may be considered to fabricate the shaft through an injection molding process using a mold. However, the mold in this case must be configured in the form of split-type which can be separated radially and the generation of burrs on the planes to be separated after molding is unavoidable, and thus causes a hindrance to the stable sliding operation of the carriage. As a result, it has not yet been put into practice.
(iii) Since the conveyance of the recording sheet is generally carried out by transmitting the return motion of the carriage to cam members to actuate conveyance rollers, it is not possible to speed up the recording operation. If the motor is forcibly driven at higher speeds in order to speed up the recording operation, it would pose various problems such as noises and durability.